1. Field of the Invention
This invention relates generally to a power transfer mechanism adapted to be incorporated in a multiple path drive system, for example, a four-wheel drive vehicle. More particularly, it relates to a torque transfer case adapted to receive torque from a prime mover and to provide torque for one drive axle where two-wheel drive is adequate, and to provide torque for both drive axles automatically where four-wheel drive is required. The torque transfer case may be assembled in either of two configurations using interchangeable parts.
2. Description of the Prior Art
In recent years there have been many improvements in automotive drive trains, including improvements relating to the transfer of torque from a prime mover to drive axles. Where four-wheel drive systems are used, transfer cases have been developed which generally provided torque transfer to one output to drive an axle and to another output for driving another axle. Some such transfer cases generally have included some form of differential mechanism for allowing relative rotation between the output shafts. Suitable controls were provided for engaging and disengaging the four-wheel drive function externally, as desired. Other such transfer cases included a mechanism which automatically engages and disengages the four-wheel drive function. Separate torque transfer cases provided for establishing each torque transfer path desired. Transfer cases have been developed for providing torque transfer from an input to one output coaxial therewith and another output offset therefrom. Other transfer cases have been developed for providing torque transfer from an input to a pair of offset outputs. There remains a need to provide a single torque transfer case which may be assembled economically for providing torque transfer in either configuration, as desired.
Accordingly, it is an object of this invention to meet the continuing need and desire in the art for improvements in the transmission of torque by providing an improved torque transfer mechanism which normally provides torque transfer to one output shaft for establishing a two-wheel drive condition, and which automatically engages for providing torque transfer to two output shafts for establishing a four-wheel drive condition. The improved mechanism is easily adaptable to either of two configurations to provide desired torque transfer paths in a four-wheel drive vehicle. The adaptability results in a simple and economic torque transfer mechanism which is easy to fabricate and assemble.